A MO(V) MONOPHOSPHATE WITH A TUNNEL STRUCTURE - K-3(MOO)(4)(PO4)(5)

A Mo(V) monophospate has been synthesized for the first time. It cryst allizes in the space group Pbca with a = 9.676(2) Angstrom, b = 14.366 (2) Angstrom, and c = 28.391(5) Angstrom. The host lattice of this pho sphate consists of corner-shaning MoO6 octahedra and PO4 tetrahedra fo rming two kinds of six-sided tunnels running along c where the K+ ions are located. Each PO4 tetrahedron shares its four apices with the Mo( V) octahedra, whereas each Mo(V) octahedron shares five apices with th e tetrahedra, its sixth apex being free. Six-sided tunnels running alo ng b that intersect the large tunnels running along a are also observe d. The distribution of Kf in the different types of tunnels is studied . (C) 1995 Academic Press,Inc.